Apparatus for feeding and stacking loose paper sheets

ABSTRACT

An apparatus for feeding and stacking loose paper sheets having a stacking station with an upstanding end stop for the sheets to be stacked and a lower and upper endless conveyor belt for clamping the sheets to be stacked therebetween and feeding the sheets to the stacking station. The lower conveyor belt extends underneath the stacking station and the upper conveyor belt passes around a return roller arranged a small distance upstream of the stacking station. Side guide members are arranged on each side of the lower conveyor belt for supporting the side portions of the sheets which side guide members are inclined from the lower conveyor belt downwardly and outwardly whereby the sheets are bent in the transverse direction. The side guide members and the lower conveyor belt have portions extending obliquely upward in the direction of feed of the sheets from a point lying upstream of the forward or upstream side of the stacking station to a point lying under the stacking station whereby any sheet fed without being overlapped by the preceding sheet can be pushed without disturbance, and without damaging its front edge, under the stack formed at the stacking station.

United States Patent de Ridder [54] APPARATUS FOR FEEDING AND STACKINGLOOSE PAPER SHEETS [72] Inventor: Gerardus Johannes de Ridder, Bussum,Netherlands [73] Assignee: Ingenieursbureau De Ridder N.V., Baam,Netherlands [22] Filed: April 7, 1971 [21] Appl. No.: 131,930

[30] Foreign Application Priority Data April 10, 1970 Netherlands..7005222 [52] U.S. Cl ..271/75, 271/86 [51] Int. Cl ..B65h 29/16, B65h31/00 [58] Field of Search ..271/63, 75, 86; 198/35; 214/62 [56]References Cited UNITED STATES PATENTS 3,212,774 10/1965 lngalls...271/86 X Primary ExaminerEdward A. Sroka Attorney-Waters, Roditi',Schwartz & Nissen [451 Sept. 19,1972

[57] ABSTRACT An apparatus for feeding and stacking loose paper sheetshaving a stacking station with an upstanding end stop for the sheets tobe stacked and a lower and upper endless conveyor belt for clamping thesheets to be stacked therebetween and feeding the sheets to the stackingstation. The lower conveyor belt extends underneath the stacking stationand the upper conveyor belt passes around a return roller arranged asmall distance upstream of the stacking station. Side guide members arearranged on each side of the lower conveyor belt for supporting the sideportions of the sheets which side guide members are inclined from thelower conveyor belt downwardly and outwardly whereby the sheets are bentin the transverse direction. The side guide members and the lowerconveyor belt have portions extending obliquely upward in the directionof feed of the sheets from a point lying upstream of the forward orupstream side of the stacking station to a point lying under thestacking station whereby any sheet fed without being overlapped by thepreceding sheet can be pushed without disturbance, and without damagingits front edge, under the stack formed at the stacking station.

PATENTEI'JSEP 19 L972 SHEET 2 [IF BACKGROUND OF THE INVENTION Theinvention generally relates to apparatus for feeding and stacking loosepaper sheets. More in particular, the invention relates to suchapparatus comprising a lower endless conveyor belt and an upper endlessconveyor belt adapted to clamp the sheets to be stacked between them forfeeding the sheets to a stacking station having an upstanding end stopfor the sheets at the front or downstream side thereof, in which thelower endless belt extends under the stacking station and the upperendless belt passes around a return roller mounted for vertical movementa short distance upstream of the stacking station and urged downwardstowards the lower endless belt. In this connection, the term loosesheets of paper means not only single sheets but also sheets folded anumber of times, such as newspapers, periodicals, leaflets, and thelike.

An apparatus of the above-mentioned kind is described in my co-pendingUS. Pat. application Ser. No. 5 l,l84 and the construction describedtherein is intended particularly for stacking freshly printed newspaperswhich are delivered in rapid succession by the conveyor belts to thestacking station in a continuous stream, the sheets being held betweenthe upper and lower conveyor belts while overlapping one another in apantile-like arrangement with the forward edge part of each sheetunderlying the rear edge part of the preceding sheet. At thestacking-station, the sheets fed thereto thus successively slideunderneath the stack being formed, to be lifted off by a periodicallyactivated separating device after a stack of newspapers containing apre-determined number of sheets has been formed which stack may then bedischarged by further conveyor means. In this arrangement of my saidcopending application, the conveyor belt runs over rollers which aremounted in a frame articulated on the feed side of the apparatus, sothat under the weight of this frame the upper conveyor belt is pressedonto the stream of sheets fed forward .and can aline itself in thevertical direction in accordance with the thickness of the paper sheets.The apparatus further comprises side guide members arranged on bothsides of the lower conveyor belt for supporting the side portions of thesheets which side guide members are inclined from the lower conveyorbelt downwardly and laterally outwardly. The sheets supported by theseside guide members are thus bent in the transverse direction whereby thepaper stream fed forward and also the stack formed therefrom is givenadequate stiffness in the longitudinal direction to prevent the sheetsfrom undergoing relative displacement and to enable the sheets to slidesmoothly under one another at the stacking station, while at the sametime the separation and-removal of the finished stacks are facilitatedthereby.

In a stacking apparatus of the kind described the problem arises that iffor any reason the continuous stream of paper is interrupted the frontedge of the first sheet following this interruption can strike againstthe rear edge of the preceding sheet and consequently finds it difficultto slide under the stack, so that serious disturbances may occur. Thisdifficulty also arises when the sheets are not fed in an overlappingpantile arrangement, but follows one another at a shorter or longerdistance.

2 SUMMARY OF THE INVENTION Accordingly, the invention has for its mainobject to provide a feeding and stacking apparatus of the abovedescribed kind which overcomes these difficulties and whichallows asmooth stacking operation also in case successive sheets fed by theconveyor belts do not overlap one another. r

To this end, in the apparatus according to the inven- 0 tion the sideguide members have portions extending obliquely upwards in the feeddirection of the sheets from a point lying upstream of the forward orupstream side of the stacking station to a point lying under thestacking station and in a similar way means are provided for guiding thelower conveyor belt obliquely upwards from a point upstream of theforward side of the stacking station to a point underneath the stackingstation. In this way any sheet fed without being overlapped by thepreceding sheet is guided under the stack formed at the stacking stationand can be pushed under this stack without disturbance and withoutdamaging its front edge since this edge cannot come into contact withthe rear edge of the lowermost sheet of the stack.

According to a preferred embodiment of the invention the lower conveyorbelt has a support provided with an aperture which extends from a pointsome distance, upstream to a point downstream of the rear side of thestacking station and under the return roller for the upper conveyorbelt, a supporting rollerfor the lower conveyor belt being disposed insaid aperture, so that downstream of said supporting roller the returnroller presses the lower conveyor belt downwards in a curve. As long asa continual stream of paper composed of overlapping sheets of paper isfed, these sheets of paper, taken as a whole, have sufficient stiffness,because of their transverse bending, to ensure that the return roller ispractically unable to press the sheets and the bottom conveyor beltrunning under them downwards in a curve downstream of the supportingroller, or can do so only to a very slight extent, so that the paperstream runs into the stacking station on a practically rectilinear path.As soon as the stream of paper sheets is interrupted, however, becauseof the lack of overlapping the front edge of the sheet following thisinterruption will offer substantially less resistance to the downwardlydirected compressive force of the return roller of the upper conveyorbelt, so that said return roller can now easily press the front edge ofsaid sheet downwards in a curve, and thus the edge can be effectivelypushed under the rear edge of the preceding sheet and thus under saidsheet.

BRIEF DESCRIPTION OF THE DRAWINGS PREFERRED EMBODIMENT OF THE INVENTIONThe apparatus illustrated is provided with a lower conveyor belt 1 whichis driven in the direction of the arrow in FIG. 1 and which feeds andsupports in the center thereof the paper sheets 2, for examplenewspapers, to be stacked. This conveyor belt 1 runs under the stackingstation 3 of the apparatus to a driving and return roller 4, from whichit returns to the inlet side of the apparatus (not shown). The upper,operative run of this conveyor belt 1 runs over a support bar which isformed by a channel section 5 the side flanges of .which point downwardsand the web of which is wider that the conveyor belt 1 running over it.At its front or downstream side the stacking station 3 isprovided withan end stop 6 which is upstanding transversely to the conveyor belt 1and against which the fed sheets 2 strike by their front edge, 50 that astack 7 of sheets is formed. The paper sheets 2 are normally fed in acontinuous stream, overlapping one another in a pantile arrangement withthe front edge of each sheet extending a certain distance under thepreceding sheet. The stack 7 isconsequently formed from below, thesuccessive sheets being pushed under one another one after the other.The stacking station is also provided with arrangements (not shown inthe drawings) for separating and discharging the stacks, each of whichconsists of a given number of sheets, and together with the appertainingseperating and discharge devices may for example be constructed asdescribed in my previously mentioned co-pending US. Pat. applicationSer. No. 51,184.

A driven upper conveyor belt 8 moves over the bottom conveyor belt 1 andruns from a drive roller 9 downwards to a guide roller 10 and from thelatter forwards to a return roller 11 which is situated a short distanceupstream of the rear side of the stacking station 3 or stack 7 and fromwhich this upper conveyor belt then returns over a tensioning roller 12to the drive roller 9. The rollers l0, l1 and 12 are mounted on arms l3,l4 and 15 of an upper frame which is swivellable about the axis of thedrive roller 9, so that under the weight of this frame the conveyor belt8 is pressed onto the stream of sheets 2 supported on the conveyor belt1, whereby the upper belt 8 can adapt itself to the thickness of thesheets being fed. The conv'eyor belts 1 and 8 are in addition driven atthe same speed, so that they clamp the paper sheets between them in thecenter and together move them forwards. The'lower structure of theapparatus, which is only indicated'diagrammatically in the drawings, maybe constructed as described in detail in my above-mentioned co-pendingpatent application.

The channel section or support bar 5 for the lower conveyor belt 2 hasan aperture 16, the web of this channel section being cut out in aregion which extends from a point lying some distance upstream of therear side of the stacking station 3. to a point lying some distancedownstream of this rear side. In the opening formed in this manner thereis mounted between the side flanges of the section 5 a freely rotatablesupporting roller 17 which has a larger diameter than the returnrollerll of the upper conveyor belt 8 and the axis of which is disposeda short distance upstream of the axis of said return roller 1 I, viewedin the direction of movement of the paper sheets, as can be seen fromFIG. 1.

A guide plate 18 adjoins said support bar 5 on each side and dropslaterally obliquely downwards from said bar 5. These two guide plates 18serve to support the side portions of the sheets 2 being fed, .so thatthese sheets assume a curved shape in the transverse direction and thepaper stream formed by them is given the desired stiffness in thelongitudinal direction. Thereby the individual sheets will have lesstendency to be displaced in relation to one another and can more easilybe pushed under the stack 7 being formed. These guide plates 18 alsoextend under the stack 7, so that the latter is also given a profilewhich is curved in the transverse direction. I

These guide plates 18 have a portion 19 which extends in the directionof movement of the paper sheets to a point directly upstream of thestacking station 3 and has a greater lateral inclination than theportion 20 of the guide plates which lies below the stacking station 3.Between these plate portions 19 and 20 of the plates there is situated atransition portion 21 which extends obliquely upwards in thelongitudinal direction of the plates and which merges with correspondingrounded transitions into the portions 19 and 20. Upstream of the plateportion 19, a plate portion 23 extends which has the same lateralinclination as the plate portion 20 and which merges into the plateportion 19 by way of a corresponding transition portion 22.

When the individual paper sheets 2 are fed in an uninterrupted paperstream, overlapping one another, as illustrated in FIG. 1, they have asa whole adequate stiffness to be able to withstand the pressure of thereturn roller 11 of the upper conveyor belt 8, so that the paper streamruns practically in a rectilinear path over the supporting roller 17 andunder the return roller 11 to the stacking station and under the stackof sheets 7. The side portions of all the sheets of paper 2 of thiscontinuous stream rest on the lateral guide plates 18, sagging furtherdownwards in the region of the plate portions 19.

As soon as an interruption occurs in the paper stream, however, thefront end of the firstsheet following the interruption has reducedstiffness because of the lack of an overlap, so that this front edge 24(FIGS. 1 and 2)together with the conveyor belt 1 is pressed downwardsunder the pressure'of the return roller 11 on leaving the supportingroller 17 whereby between the latter and the end of the aperture 16 inthe support bar 15 the conveyor belt 1 is guided in a downward curve 25(FIG. 1) which penetrates under the rear edge of the paper stack 7.Consequently, the center of the front edge 24 of said sheet 2 isintroduced under the rear edge of the lowermost sheet of the stack 7 andinto the stacking station without striking against this rear edge of thelowermost sheet of the stack 7. On both sides of the bottom conveyorbelt 1 the front edge 24 of this foremost sheet slides over the guideplate portions 19 and under the rear edge of the stack 7 resting on theguide plate portions 20, this front edge then moving along thetransition portions 21 of the guide plates upwards past said rear edgeof the stack, so that here again the front edge 24 cannot strike againstthe stack. In order to ensure that the side portions of the sheets lieclose against the guide plate portions 19, pressure rollers 26 arepreferably disposed on both sides of the upper conveyor belt 8, drivenauxiliary belts 27 running over said pressure rollers (FIG. 2).

Through the abovedescribed apparatus according to the invention theeffect is consequently achieved that the sheets being fed are alwayspushed under the sheets already stacked, even when in consequence of aninterruption in the usually continuous paper stream these sheets do notoverlap one another. With the apparatus according to the invention it istherefore also possible for sheets which for any special reason areintroduced between the two conveyor belts l and 8 without overlapping,to be stacked in the manner described above without disturbance.

In my above mentioned co-pending patent application the frame carryingthe upper conveyor belt is adjustable in the longitudinal direction inorder to be able to adapt the position of the return roller 11, inrelation to the stationary end stop 6, to the length of the paper sheets2 in the direction of feed, in sucha manner that said return rolleralways lies a short distance upstream of the stack 7 formed. In theapparatus described above this adjustment of the return roller 11 mustnaturally also be accompanied by adjustment of the supporting roller 17and the guide plates 18 in the longitudinal direction. For this reason,these parts are also slidable in the longitudinal direction of theapparatus, in a manner not illustrated, in which they may be coupled tothe movable upper frame of the apparatus.

While the invention has been shown and described with reference to aspecific embodiment thereof, various modifications of this embodimentmay be resorted to within the scope of the following claims.

What is claimed is:

1. An apparatus for feeding and stacking loose paper sheets comprising astacking station having a forward and a rear side, a driven lowerendless conveyor belt extending under said stacking station andreturning at a point downstream of the latter, an upper endless conveyorbelt, a return roller for said upper conveyor belt arranged a shortdistance upstream of said stacking station, means for mounting saidreturn roller for vertical movement while urging said roller downwardswhereby said lower and upper conveyor belts may clamp the sheets to bestacked between them in the central area thereof to feed said sheets tosaid stacking station, said stacking station having an upstanding endstop for said sheets disposed at the front or downstream side thereof,two lateral guide members one arranged on each side of said lowerconveyor belt for supporting side portions of said sheets laterally ofsaid sheet central area, said lateral guide members being inclined fromsaid lower conveyor belt downwardly and laterally outwardly whereby saidsheets assume a curved shape in the transverse direction, said lateralguide members having portions extending obliquely upwards in the feeddirection, of the sheets from a point lying upstream of the rear orupstream side of said stacking station to a point lying under saidstacking station, and means for guiding said lower conveyor beltobliquely upwards from a point lying upstream of said rear side of saidstacking station to a point under said stacking station whereby anysheet fed without being overlapped by the preceding sheet can be pushedwithout disturbance and without damage to its front edge under the stackformed at the stacking station.

2. The apparatus of claim 1 further comprising a support member for saidlower conveyor belt having an aperture extending from a point somedistance upstream of to a point some distance downstream of said rearside of said stacking station and underneath said return roller for saidupper conveyor belt, and a supporting roller for said lower conveyorbelt arranged in said aperture in a position in which its axis liesupstream of the axis of said upper conveyor belt return roller wherebydownstream of said supporting roller the lower conveyor belt can bepressed downwards in a curve by said return roller.

3. The apparatus of claim 2 in which said support member for said lowerconveyor belt comprises a channel section arranged with its lateralflanges directed downwards, said channel section having a web which iswider than the lower conveyor belt, said web being cut out to form saidaperture and said supporting roller being arranged between the flangesof said channel section and projecting from below into this cutout.

4. The apparatus of claim 2 in which said lateral guide members compriseguide plates adjoining said support member for said lower conveyor beltand extending obliquely and laterally downwards therefrom, said guideplates each merging from a point situated a short distance upstream ofsaid rear side of said stacking station, by way of a transition portionextending obliquely upwards in the feed direction of the sheets, from adetermined lateral inclination upstream of said stacking station into alesser lateral inclination under said stacking station.

5. The apparatus of claim 4 further comprising pressure roller meansarranged on both sides of said upper conveyor belt a short distanceupstream of said stacking station, said auxiliary roller means beingadapted to press said side portions of said sheets against said guideplates.

6. The apparatus according to claim 2 in which said return roller forsaid upper conveyor belt and said supporting roller for said lowerconveyor belt are together mounted for adjustment in the longitudinaldirection of the apparatus whereby the latter can be adapted to the sizeof the sheets to be stacked.

1. An apparatus for feeding and stacking loose paper sheets comprising astacking station having a forward and a rear side, a driven lowerendless conveyor belt extending under said stacking station andreturning at a point downstream of the latter, an upper endless conveyorbelt, a return roller for said upper conveyor belt arranged a shortdistance upstream of said stacking station, means for mounting saidreturn roller for vertical movement while urging said roller downwardswhereby said lower and upper conveyor belts may clamp the sheets to bestacked between them in the central area thereof to feed said sheets tosaid stacking station, said stacking station having an upstanding endstop for said sheets disposed at the front or downstream side thereof,two lateral guide members one arranged on each side of said lowerconveyor belt for supporting side portions of said sheets laterally ofsaid sheet central area, said lateral guide members being inclined fromsaid lower conveyor belt downwardly and laterally outwardly whereby saidsheets assume a curved shape in the transverse direction, said lateralguide members having portions extending obliquely upwards in the feeddirection of the sheets from a point lying upstream of the rear orupstream side of said stacking station to a point lying under saidstacking station, and means for guiding said lower conveyor beltobliquely upwards from a point lying upstream of said rear side of saidstacking station to a point under said stacking station whereby anysheet fed without being overlapped by the preceding sheet can be pushedwithout disturbance and without damage to its front edge under the stackformed at the stacking station.
 2. The apparatus of claim 1 furthercomprising a support member for said lower conveyor belt having anaperture extending from a point some distance upstream of to a pointsome distance downstream of said rear side of said stacking station andunderneath said return roller for said upper conveyor belt, and asupporting roller for said lower conveyor belt arranged in said aperturein a position in which its axis lies upstream of the axis of said upperconveyor belt return roller whereby downstream of said supporting rollerthe lower conveyor belt can be pressed downwards in a curve by saidreturn roller.
 3. The apparatus of claim 2 in which said support memberfor said lower conveyor belt comprises a channel section arranged withits lateral flanges directed downwards, said channel section having aweb which is wider than the lower conveyor belt, said web being cut outto form said aperture and said supporting roller being arranged betweenthe flanges of said channel section and projecting from below into thiscutout.
 4. The apparatus of claim 2 in which said lateral guide memberscomprise guide plates adjoining said support member for said lowerconveyor belt and extending obliquely and laterally downwards therefrom,said guide plates each merging from a point situated a short distanceupstream of said rear side of said stacking station, by way of atransition portion extending obliquely upwards in the feed direction ofthe sheets, from a determined lateral inclination upstream of saidstacking station into a lesser lateral inclination under said stackingstation.
 5. The apparatus of claim 4 further cOmprising pressure rollermeans arranged on both sides of said upper conveyor belt a shortdistance upstream of said stacking station, said auxiliary roller meansbeing adapted to press said side portions of said sheets against saidguide plates.
 6. The apparatus according to claim 2 in which said returnroller for said upper conveyor belt and said supporting roller for saidlower conveyor belt are together mounted for adjustment in thelongitudinal direction of the apparatus whereby the latter can beadapted to the size of the sheets to be stacked.